use google API to get match lon/lat data to country and state

reverseGeo

reverseGeo <- function(latlng) {
    require("XML")
    require("httr")
    latlng <- as.numeric(latlng)
    latlngStr <- gsub(" ", "%20", paste(round(latlng, 2), collapse = ","))
    url <- "http://maps.google.com"
    path <- "/maps/api/geocode/xml"
    query <- list(sensor = "false", latlng = latlngStr)
    response <- GET(url, path = path, query = query)
    if (response$status != 200) {
        print(paste("HTTP Error:", response$status), quote = F)
        return(c(NA, NA))
    }
    xml <- xmlInternalTreeParse(content(response, type = "text"))
    status <- xmlValue(getNodeSet(xml, "//status")[[1]])
    if (status != "OK") {
        print(paste("Query Failed:", status), quote = F)
        return(c(NA, NA))
    }
    xPath <- "//result[1]/address_component[type=\"country\"]/long_name[1]"
    country <- xmlValue(getNodeSet(xml, xPath)[[1]])
    xPath <- "//result[1]/address_component[type=\"administrative_area_level_1\"]/long_name[1]"
    state <- xmlValue(getNodeSet(xml, xPath)[[1]])
    return(c(state = state, country = country))
}